On Mon, Aug 20, 2018 at 06:30:57PM -0700, Daniel Rosenberg wrote:
> Userspace can cause the kref to handles to increment
> arbitrarily high. Ensure it does not overflow.
>
> Signed-off-by: Daniel Rosenberg <dro...@google.com>
> ---
>
> This patch is against 4.4. It does not apply to master due to a large
> rework of ion in 4.12 which removed the affected functions altogther.
> It applies from 3.18 to 4.11, although with a trivial conflict resolution
> for the later branches.
> 4c23cbff073f3b9b ("staging: android: ion: Remove import interface")
>
> drivers/staging/android/ion/ion.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/android/ion/ion.c
> b/drivers/staging/android/ion/ion.c
> index 374f840f31a48..11f93a6314fdb 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -15,6 +15,7 @@
> *
> */
>
> +#include <linux/atomic.h>
> #include <linux/device.h>
> #include <linux/err.h>
> #include <linux/file.h>
> @@ -387,6 +388,15 @@ static void ion_handle_get(struct ion_handle *handle)
> kref_get(&handle->ref);
> }
>
> +/* Must hold the client lock */
> +static struct ion_handle *ion_handle_get_check_overflow(
> + struct ion_handle *handle)
> +{
> + if (atomic_read(&handle->ref.refcount) + 1 == 0)
> + return ERR_PTR(-EOVERFLOW);
> + ion_handle_get(handle);
> + return handle;
> +}
> +
> static int ion_handle_put_nolock(struct ion_handle *handle)
> {
> int ret;
I tried to apply this patch, but it looks like you hand-edited it which
made it impossible to apply. Did you do that, or did git really create
this broken diff exactly as-is?
Try applying this patch yourself, you will see the error. I could fix
it by manually editing the diff metadata but I really shouldn't have to
as that implies you did not test the patch you sent me :(
thanks,
greg k-h
